Technical Field
The present invention relates to two-phase heat transfer devices, in particular mechanically passive devices with a two-phase fluid loop that are capillary-driven or gravity-driven.
Description of the Related Art
It is known from document FR-A-2949642 that such devices are used as cooling means for electrotechnical power converters.
These devices can be temperature-controlled by controlling the pressure in the reservoir. This control can be active (electric heating resistor) or entirely passive (introduction of an auxiliary gas into the reservoir).
However, it has appeared that the startup phases were particularly subject to problems for high thermal power levels, drying-out of the capillary wick can occur resulting in a startup failure.
Moreover, if the device is subjected to accelerations, a phenomenon known as ‘cold shock’ may occur in the reservoir which suddenly lowers the pressure and degrades performance.
Furthermore, strong fluctuations in the thermal load can lead to operational instability of the two-phase loop.
There therefore appeared a need to increase on the one hand the startup reliability and on the other hand the operational reliability of such loops under conditions of thermal loads presenting strong fluctuations.